Engine assembly with engine and cooler compartments

ABSTRACT

An engine assembly includes an engine compartment containing an internal combustion engine and a cooler compartment adjacent the engine compartment containing a heat exchanger. The engine and cooler compartments have an opening defined therebetween. A forced air system is operable to drive an airflow. A method for cooling the engine and its compartment is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/666,773, filed Aug. 2, 2017, which claims priority from U.S.provisional application No. 62/526,541 filed Jun. 29, 2017, the entirecontents of which are incorporated by reference herein.

TECHNICAL FIELD

The application relates generally to engine assemblies with internalcombustion engines and, more particularly, to systems and methods usedto cool such engines.

BACKGROUND OF THE ART

In some aircraft, for example helicopters, space may be limited for theinstallation of one or more engine(s). Liquid-cooled internal combustionengines typically require a cooler to cool the liquid coolant of theengine(s), as well as a blower or other forced air system to drive acooling airflow through the cooler. In some instances, available spacein the vehicle is limited, which may prevent the engine and cooler frombeing received in a common compartment. This may increase the coolingrequirements for the engine, and thus require a further increase in thesize of the cooler.

SUMMARY

In one aspect, there is provided an engine assembly, comprising: anengine compartment containing an internal combustion engine, theinternal combustion engine having internal cooling circuitry for fluidcooling of the engine, the engine compartment having an air intakefluidly connecting an interior of the engine compartment to anenvironment of the engine assembly; a cooler compartment separate fromand adjacent the engine compartment, the cooler compartment containing aheat exchanger fluidly connected to the cooling circuitry of theinternal combustion engine, an interior of the cooler compartmentfluidly connected to the environment via an inlet and an outlet; ametered opening fluidly connecting the engine compartment to the coolercompartment; and a forced air system fluidly between the inlet and theoutlet and operable to drive an airflow from the inlet to the outletthrough the heat exchanger, and from the intake to the outlet throughthe metered opening

In another aspect, there is provided an engine assembly comprising: acompartment having separate engine and cooler sections fluidly connectedwith each other through an opening, the engine section having an airintake fluidly connecting an interior of the engine section to anenvironment of the engine assembly, an interior of the cooler sectionfluidly connected to the environment of the engine assembly via an inletand an outlet; a compound engine received in the engine section andincluding a compressor in fluid communication with the environment ofthe engine assembly, an internal combustion engine having an inlet influid communication with an outlet of the compressor, and a turbinehaving an inlet in fluid communication with an exhaust of the internalcombustion engine, the turbine compounded with the internal combustionengine, the compressor in driving engagement with at least one of theturbine and the internal combustion engine; a heat exchanger received inthe cooler section, the heat exchanger fluidly connected to a fluidcircuitry of the compound engine, the interior of the cooler sectionfluidly connected to the inlet of the cooler section via the heatexchanger; and a forced air system operable to drive an airflow, theforced air system in simultaneous fluid communication with a main flowpath and a secondary flow path, the main flow path extending from theinlet of the cooler section to the outlet of the cooler section via theheat exchanger and the interior of the cooler section, the secondaryflow path extending from the air intake of the engine section to theoutlet of the cooler section via the interior of the engine section, theopening and the interior of the cooler section.

In another aspect, there is provided a method for cooling an internalcombustion engine received in an engine compartment separated from acooler compartment, the method comprising: expelling air from the coolercompartment to an environment with a forced air system to simultaneouslycreate main and secondary airflows, wherein: creating the main airflowincludes drawing outside air in the cooler compartment from theenvironment separately from the engine compartment; and creating thesecondary airflow includes drawing additional air in the coolercompartment from the engine compartment through an opening fluidlyconnecting the cooler and engine compartments.

In a further aspect, there is provided an engine assembly within anaircraft vehicle, the vehicle having a longitudinal axis definedgenerally from a front end to a rear end, the engine assemblycomprising: an engine compartment and a cooler compartment seriallydisposed in a direction of the longitudinal axis of the vehicle, theengine and cooler compartments separated from one another; an internalcombustion engine disposed within the engine compartment; a heatexchanger disposed within the cooler compartment; a forced air system inthe cooler compartment operable to drive an airflow through the heatexchanger.

DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying figures in which:

FIG. 1 is a schematic view of an engine assembly in accordance with aparticular embodiment;

FIG. 2 is a schematic view of a vehicle containing two engine assembliessuch as shown in FIG. 1, in accordance with a particular embodiment;

FIG. 3 is a schematic tridimensional view of an implementation of theengine assembly of FIG. 1 in the vehicle of FIG. 2, in accordance with aparticular embodiment;

FIG. 4 is a schematic partially transparent top view of theimplementation of FIG. 3; and

FIG. 5 is a schematic partially transparent side view of theimplementation of FIG. 3.

DETAILED DESCRIPTION

Referring to FIG. 1, an engine assembly 10 is generally shown andincludes an internal combustion engine 12. In a particular embodiment,the internal combustion engine 12 comprises one or more rotary unitseach configured for example as a Wankel engine, or one or morereciprocating pistons. The internal combustion engine 12 drives a shaft14 that is used for driving a rotatable load (not shown). It isunderstood that the engine assembly 10 may alternately be configured todrive any other appropriate type of load, including, but not limited to,one or more generator(s), propeller(s), accessory(ies), rotor mast(s),compressor(s), or any other appropriate type of load or combinationthereof. In a particular embodiment, the internal combustion engine 12is a rotary engine comprising three rotary units each configured as aWankel engine, with a rotor cavity having a profile defining two lobes,preferably an epitrochoid, in which a rotor is received with thegeometrical axis of the rotor being offset from and parallel to the axisof the rotor cavity, and with the rotor having threecircumferentially-spaced apex portions and a generally triangularprofile with outwardly arched sides, so as to define three rotatingcombustion chambers with variable volume.

In a particular embodiment, the engine assembly 10 is a compound cycleengine system or compound cycle engine such as described in Lents etal.'s U.S. Pat. No. 7,753,036 issued Jul. 13, 2010 or as described inJulien et al.'s U.S. Pat. No. 7,775,044 issued Aug. 17, 2010, or asdescribed in Thomassin et al.'s U.S. patent publication No. 2015/0275749published Oct. 1, 2015, or as described in Bolduc et al.'s U.S. patentpublication No. 2015/0275756 published Oct. 1, 2015, the entire contentsof all of which are incorporated by reference herein. The engineassembly 10 may be used as a prime mover engine, such as on an aircraftor other vehicle, or in any other suitable application.

The engine assembly 10 comprises an engine compartment 16 containing theinternal combustion engine 12. The engine compartment 16 has an airintake 18 fluidly connecting an interior 20 of the engine compartment 16to an environment 22 of the engine assembly 10. The engine assembly 10further has a cooler compartment 24 adjacent the engine compartment 16.In the illustrated embodiment, the engine compartment 16 and the coolercompartment 24 are serially disposed in a direction A parallel to theshaft 14 of the internal combustion engine 12.

In the embodiment shown, the engine assembly 10 further includes acompressor 54 for compressing the air before it is fed to an air inlet56 of the internal combustion engine 12, and a turbine section 58receiving the exhaust gases from the internal combustion engine 12. Itis understood that variations are possible, and that, for example, thecompressor 54 and/or turbine section 58 may be omitted.

In the illustrated embodiment, the internal combustion engine 12, thecompressor 54, and the turbine section 58 are in driving engagement witha gearbox 60. The gear box 60 is configured to allow the turbine section58 to compound power with the engine shaft 14 and to allow the turbinesection 58 and/or the internal combustion engine 12 to drive thecompressor 54.

In the illustrated embodiment, the compressor 54 and the turbine section58 are in a driving engagement with the gearbox 60. In the illustratedembodiment, the compressor and turbine rotors are engaged to a sameturbine shaft 62 which is drivingly engaged to the engine shaft 14through the gearbox 60; the turbine shaft 62 and the engine shaft 14 areparallel and radially offset from one another. Alternate configurationsare possible, including, but not limited to, the rotor(s) of thecompressor 54 being engaged to a shaft separate from the turbine shaft62 (whether coaxial with the turbine shaft 62, with the engine shaft 14,or offset from both) and in driving engagement with the turbine shaft 62and/or the engine shaft 14, for example through the gearbox; and/or twoor more of the shafts 62, 16 extending at an angle (perpendicularly orotherwise) to each other.

In the depicted embodiment, the engine assembly 10 further comprises anintake plenum 70 fluidly connected to an inlet 72 of the compressor 54and to the environment 22, while an outlet 74 of the compressor 54 is influid communication with the air inlet 56 of the internal combustionengine 12, for example through a conduit 76.

The air intake 18 of the engine compartment is defined by an aperture 80through the intake plenum 70. The aperture 80 fluidly connects theenvironment 22 with the engine compartment 16 via the intake plenum 70.In a particular embodiment, the air intake 18 of the engine compartment16 is defined through a peripheral wall 82 of the engine compartment 16.Other locations of the air intake 18 of the engine compartment 16 arecontemplated.

The internal combustion engine 12 provides an exhaust flow of highpressure hot gas exiting at high peak velocity, in the form of exhaustpulses. In the illustrated embodiment, an exhaust 84 of the internalcombustion engine 12 (corresponding to or communicating with an exhaustport of a respective rotary engines/reciprocating pistons of theinternal combustion engine 12) is in fluid communication with an inlet86 of the turbine section 58 via a conduit 88. Accordingly, the exhaustflow from the internal combustion engine 12 is supplied to the turbinesection 58. The turbine section 58 may comprise a single turbine, or twoor more turbine stages in serial fluid communication; the two or moreturbine stages may have different reaction ratios from one another.Other configurations are contemplated.

In the illustrated embodiment, an outlet 90 of the turbine section 58 isfluidly connected to an inlet 92 of an exhaust duct 94 for expellingcombustion gases generated by the internal combustion engine 12 to theenvironment 22. In a particular embodiment, an insulation layer 152 isdisposed around the exhaust duct 94. In a particular embodiment, theexhaust duct 94 includes a muffler 154 for decreasing noise generated bythe engine and for treating the exhaust gases if required.

Still referring to FIG. 1, the cooler compartment 24 contains at leastone heat exchanger 28. The heat exchanger 28 has one or more firstconduit(s) 30 (one in the embodiment shown) fluidly connected to a fluidcircuitry 32 of the engine assembly 10. In the embodiment shown, thefluid circuitry 32 is a cooling circuitry of the internal combustionengine 12 (e.g., coolant passages defined through the housing of theinternal combustion engine 12) and one or more second conduit(s) 34 (aplurality in the embodiment shown) in heat exchange relationship withthe first conduit 30; alternately, the fluid circuitry may includepassages circulating coolant and/or lubricant to any suitable componentof the engine assembly 10. An interior 36 of the cooler compartment 24is fluidly connected to the environment 22 via the second conduits 34 ofthe heat exchanger 28 and via an outlet 38 spaced apart from the heatexchanger 28. The second conduits 34 of the heat exchanger 28 extendthrough, and define, an inlet 40 of the cooler compartment 24.

The engine assembly 10 further includes a wall 42, which may be afirewall, and which separates the engine compartment 16 from the coolercompartment 24. Stated otherwise, in the embodiment shown, the engineand cooler compartments 16 and 24 share a common wall 42. Alternately,one or more additional wall(s) could be provided between the enginecompartment 16 and the cooler compartment 24.

The engine compartment 16 and the cooler compartment 24 are thusdisposed on opposite sides of the wall 42. In the embodiment shown, thewall 42 is perpendicular to the axis A. The wall 42 has a meteredopening 44 defined through the wall 42. The metered opening 44 fluidlyconnects the engine compartment 16 to the cooler compartment 24. Anyother suitable feature to allow fluid communication between the enginecompartment 16 and the cooler compartment 24 may be used.

The engine assembly 10 has a forced air system 46 adjacent the coolercompartment outlet 38 and operable to drive an airflow F′. The forcedair system 46 is in simultaneous fluid communication with a main flowpath 50 and a secondary flow path 52. The main flow path 50 extendsthrough the second conduit 34 of the heat exchanger 28 to the outlet 38of the cooler compartment 24 via the interior 36 of the coolercompartment 24. The secondary flow path 52 extends from the air intake18 of the engine compartment 16 to the outlet 38 of the coolercompartment 24 via the interior 20 of the engine compartment 16, themetered opening 44 in the wall 42 and the interior 36 of the coolercompartment 24. The flow paths 50, 52 converge in the forced air system46. The source of air of both flow paths 50, 52 is the environment 22 ofthe engine assembly 10.

The forced air system 46 is configured to draw air out of the coolercompartment 24 toward the environment thereof 22. The forced air system46, by drawing air out of the cooler compartment 24, draws air from theenvironment 22 in the cooler compartment 24 through the second conduit34 of the heat exchanger 28 and draws air from the environment 22 in theengine compartment 16 through the air intake 18. The air that is drawnin the engine compartment 16 from the environment 22 passes from theengine compartment 16 to the cooler compartment 24 through the wall 42via the metered opening 44. To draw air in the cooler compartment 24,the forced air system 46 creates a pressure drop in the coolercompartment 24 such that an air pressure in the cooler compartment 24 isless than an air pressure of the engine compartment 16 and of theenvironment 22. Air is therefore drawn in the cooler compartment 24 tocompensate for this pressure drop.

In the illustrated embodiment, the exhaust duct 94 passes through anaperture 96 extending through the wall 42 separating the enginecompartment 16 from the cooler compartment 24. In the illustratedembodiment, the metered opening 44 corresponds to a gap 98, which may bean annular gap, between the exhaust duct 94 and a peripheral surface ofthe aperture 96. The gap 98 is created by the difference between thediameter of the aperture 44 and the outer diameter of the exhaust duct94. Alternately, the metered opening 44 may include one or moreaperture(s) in the wall 42 spaced apart from the aperture 96 thatreceives the exhaust duct 94, or may be defined by one or moreaperture(s) through which another structure extends, or which arecompletely free; for example, the exhaust duct 94 may extend elsewherethan through the wall 42. In the illustrated embodiment, the aperture 96is configured to be able to provide a flow in a range of from 2% to 10%of the gas turbine engine core flow, for example, 5% of the gas turbineengine core flow.

In the depicted embodiment, the exhaust duct 94 has an outlet 100fluidly connected to an inlet 102 of an exhaust plenum 104. The exhaustplenum 104 is configured for distributing the exhaust gases around theairflow F′ generated by the forced air system 46, for mixing the exhaustgases with this airflow F′. An example of this configuration isdescribed in more detail herein below.

Now referring to FIG. 2, a helicopter 112 comprises two side-by-sideengine assemblies 10 separated by a wall 160 (FIG. 4). Only one of theengine assemblies 10 of the helicopter 112 is described herein below;the other assembly 10 is identical or a mirror image of the describedassembly, and accordingly will not be described separately herein. Thehelicopter 112 has a longitudinal axis F (e.g., roll axis) extendingfrom front end 115 to a rear end 117 of the helicopter 112, and the twoengine assemblies 10 are offset along a direction perpendicular to theaxis F. The two engine assemblies 10 may be coupled to a transmission(not shown) of the helicopter 112 to drive a common load. In aparticular embodiment, a power of the twin engine assemblies 10 is from500 to 2000 horse power. A vehicle may comprise more than two engineassemblies 10.

FIGS. 3-5 illustrate an exemplary configuration for the engine assembly10 of FIGS. 1-2; other configurations are contemplated. In theembodiment shown, the engine and cooler compartments 16 and 24 aredefined in an engine bay 110 of a vehicle 112. Hence, the engine bay 110has an engine section 16 and a cooler section 24 separated from theengine section 16 by the wall 42. In a particular embodiment, the engineand cooler compartments, or sections, 16 and 24 are defined in anacelle, and serially disposed in a direction of the longitudinal axisF. The wall 42 extends transversely, for example perpendicularly, to thelongitudinal axis F. In the depicted embodiment, the engine and coolercompartments 16, 24 are streamlined and a width W (FIG. 4) of thecombined engine and cooler compartments 16, 24 defined perpendicularlyto the vehicle longitudinal axis F (FIG. 2) decreases from an upstreamend 114 to a downstream end 116 of the engine assembly 10. A height H(FIG. 5) varies from the upstream end 114 to a downstream end 116 so asto define an aerodynamic profile.

In the embodiment shown, the cooler compartment 24 include peripheralwalls 118 having apertures defining the cooler compartment inlet 40. Inthe illustrated embodiment, then engine assembly 10 has two heatexchangers 28 a and 28 b: a liquid cooler 28 a and an oil cooler 28 b.Each of the two heat exchangers 28 a and 28 b is connected to arespective fluid circuitry. The fluid circuitry of the oil cooler 28 bis connected to an oil distribution system for cooling the oil of theengine assembly 10, which may include for example oil in the gear box60, the compressor 54, the turbine 58, and/or the engine 12. The liquidcooler 28 a is configured for cooling a liquid coolant of the internalcombustion engine 12. In the illustrated embodiment, the heat exchangers28 a, 28 b are disposed on top and side walls of the cooler compartment24. The heat exchangers 28 a, 28 b cover the apertures defining thecooler compartment inlet 40 such that at least a portion of a wall or anentirety of a wall of the cooler compartment 24 is defined by the heatexchangers 28 a, 28 b. For example, the cooler compartment 24 is definedby the walls 118 extending from and connected around a perimeter of theheat exchangers 28 a, 28 b, with the inlet side of the heat exchangers28 a, 28 b being directly exposed to the environment 22, and the opposedoutlet side of the heat exchangers 28 a, 28 b being directly exposed tothe interior 36 of the cooler compartment 24. The heat exchangers 28 a,28 b are thus partly inside the cooler compartment 24 and partly exposedto the environment 22.

In the depicted embodiment and as can be best shown in FIG. 5, theconduit 76 interconnecting the compressor outlet 74 to the internalcombustion engine 12 engine assembly 10 defines an air manifold 120adjacent the internal combustion engine 12, for example for distributingthe compressor air to the rotor units. Other configurations are alsopossible.

In the embodiment shown, the forced air system 46 includes a fan, orblower, 130 disposed adjacent the cooler compartment outlet 38. As canbe best seen in FIG. 5, the fan 130 is disposed within an outlet duct132. In the depicted embodiment, the fan 130 is driven by an electricalmotor or a hydraulic motor. Other suitable motors may be used. In aparticular embodiment, the fan 130 is driven by a hydraulic or apneumatic transmission. Alternately, the fan 130 may be driven by theinternal combustion engine 12 and/or the turbine section 58. It isunderstood that any other suitable type of forced air system, including,but not limited to ejector(s), pump(s), etc., may alternately be used.

In the illustrated embodiment, the outlet duct 132 is fluidly connectedwith the cooler compartment interior 36 via the outlet 38 of the coolercompartment 24. The outlet duct 132 is affixed to one of the peripheralwalls 118 of the cooler compartment 24. In the embodiment shown, theoutlet duct 132 is affixed to a rear wall 134 (or rear firewall) of thecooler compartment 24 and extends away from the cooler compartment 24.The outlet duct 132 fluidly connects the interior 36 of the coolercompartment 24 to the environment 22 via the cooler compartment outlet38.

It can be seen that the engine and cooler compartments 16 and 24 areserially disposed in a direction of the longitudinal axis L of theoutlet duct 132. In the illustrated embodiment, the exhaust duct 94extends through an aperture 136 in the rear wall 134 of the coolercompartment 24 before being connected with the exhaust plenum 104.

Still referring to FIG. 5, in the embodiment shown the exhaust plenum104 is annular and disposed around the duct 132. The exhaust plenum 104has a circumferential outer wall 140 surrounding the outlet duct 132, anannular fore wall 142 and an annular aft wall 144. The annular fore andaft walls 142 and 144 are offset from one another along a longitudinalaxis L of the outlet duct 132 and extend radially outwardly from theoutlet duct 132. An inlet 146 of the exhaust plenum 104 is definedthrough the circumferential outer wall 140, and is connected to theexhaust duct 94 so as to receive the exhaust gases from the turbinesection 58. An outlet of the exhaust plenum 104 is defined through thewall portion 148 (FIG. 3) of the outlet duct 132 which extends withinthe exhaust plenum 104, between the walls 142, 144. Therefore, theexhaust plenum 104 is configured to output the flow of exhaust gases ina radially inward direction relative to the longitudinal axis L of theoutlet duct 132. The exhaust plenum 104 radially discharges the flow ofcombustion gases in the outlet duct 132 at a location downstream fromthe fan 130, so as to avoid exposing the fan 130 to the exhaust gases.The exhaust gases from the engine 12 are thus mixed with the airflow F′(FIG. 1) of the fan 130 within the duct 132 downstream of the fan 130before being expelled in the environment 22.

In the embodiment shown, an aft portion 150 (FIG. 5) of the outlet duct132 extends downstream of the annular aft wall 144. The flow of exhaustgases and the flow generated by the forced air system 46 are expelled inthe environment 22 through the aft portion 150.

In the depicted embodiment, the longitudinal axis L of the outlet duct132 is substantially parallel to the longitudinal axis F of thehelicopter 112 (FIG. 2). Hence, the airflow of the forced air system 46and the exhaust gases create a thrust that may overcome a portion of thedrag of the vehicle 112. Moreover, a temperature of the gas expelled inthe environment is reduced by mixing the exhaust gases from the internalcombustion engine 12 with the airflow F′ generated by the forced airsystem 46. In a particular embodiment, the temperature of the flowexiting the aft portion 150 of the outlet duct 132 is about 350° F.Other values are also possible.

Referring back to FIG. 2, each of the engine assemblies 10 of thehelicopter 112 has an outlet 200, defined by the respective aft portion150 of the outlet duct 132 (FIG. 5). In the illustrated embodiment, theoutlets 200 are side-by-side, i.e. spaced apart along a directionperpendicular to the longitudinal axis F of the helicopter. The exitflow axes L′ and L″ of the engine assemblies 10 are parallel to oneanother, and parallel or substantially parallel to the longitudinal axisF of the helicopter 112.

Referring to FIGS. 1-5, in use and in a particular embodiment, in orderto cool the internal combustion engine 12 received in the enginecompartment 16 that is separated from the cooler compartment 24 by thecommon wall 42, air is expelled from the cooler compartment 24 towardthe environment 22 with the forced air system 46 to simultaneouslycreate the main and secondary airflows 50 and 52. In the illustratedembodiment, the main airflow 50 is created by drawing outside air in thecooler compartment 24 from the environment 22 of the cooler compartment24. In so doing, the outside air is heated before it is received in thecooler compartment 24 by cooling a fluid of the internal combustionengine 12 or of the engine assembly 10. For example, the fluid may beoil of the internal combustion engine 12 and/or of the engine assembly10 as a whole, and/or a liquid coolant for the internal combustionengine 12. The secondary air flow 52 is created by drawing air in thecooler compartment 24 from the engine compartment 16 through the meteredopening 44 in the common wall 42.

In the illustrated embodiment, the metered opening 44 is the gap 98between the peripheral surface of the aperture 96 of the common wall 42and the exhaust duct 94 that passes through the aperture 96. The enginecompartment is cooled by passing air from the engine compartment 16 tothe cooler compartment 24 through the gap 44 around the exhaust duct 94.

In a particular embodiment, expelling air from the cooler compartmentincludes mixing the expelled air with the exhaust from the internalcombustion engine 12, and/or generating thrust with the expelled air.

The above description is meant to be exemplary only, and one skilled inthe art will recognize that changes may be made to the embodimentsdescribed without departing from the scope of the invention disclosed.Modifications which fall within the scope of the present invention willbe apparent to those skilled in the art, in light of a review of thisdisclosure, and such modifications are intended to fall within theappended claims.

The invention claimed is:
 1. An engine assembly within an aircraftvehicle, the aircraft vehicle having a longitudinal axis defined from afront end to a rear end, the engine assembly comprising: an enginecompartment and a cooler compartment serially disposed in a direction ofthe longitudinal axis of the vehicle, the engine and cooler compartmentsseparated from one another; an internal combustion engine disposedwithin the engine compartment; a heat exchanger disposed within thecooler compartment; a forced air system in the cooler compartmentoperable to drive an airflow through the heat exchanger and; an exhaustduct fluidly connecting an exhaust of the internal combustion enginewith an environment of the engine assembly, the exhaust duct extendingthrough the cooler compartment.
 2. The engine assembly as defined inclaim 1, wherein the engine and cooler compartments are separated fromone another by a firewall.
 3. The engine assembly as defined in claim 2,wherein the firewall extends transversely to the longitudinal axis. 4.The engine assembly as defined in claim 1, wherein the heat exchanger isadjacent an inlet of the cooler compartment.
 5. The engine assembly asdefined in claim 1, wherein the heat exchanger is fluidly connected to acooling circuitry of an internal combustion engine of the engineassembly.
 6. The engine assembly as defined in claim 1, wherein theforced air system is operable to drive an airflow along a flow pathextending from an inlet of the cooler compartment to an outlet of thecooler compartment through the heat exchanger and an interior of thecooler compartment, the heat exchanger providing heat exchangerelationship between a fluid of the internal combustion engine of theengine assembly and the airflow from the forced air system.
 7. Theengine assembly as defined in claim 1, wherein the forced air systemincludes an outlet duct defining the communication between an outlet ofthe cooler compartment and the environment of the engine assembly, theengine compartment and the cooler compartment being serially disposed ina direction of a longitudinal axis of the outlet duct.
 8. The engineassembly as defined in claim 1, wherein the internal combustion engineand the cooler compartment are serially disposed in a direction parallelto a shaft of the internal combustion engine.
 9. The engine assembly asdefined in claim 1, wherein a width of the engine assembly decreasesalong the longitudinal axis toward the rear end of the aircraft vehicle.10. An aircraft vehicle including two engine assemblies eachcorresponding to the engine assembly as defined in claim 1, wherein thetwo engine assemblies are laterally offset from one another.